I understand that the hardware between the original Nvidia Shield tablet and the newer Nvidia K1 tablet is virtually identical. What I haven't been able to garner from many internet searches is if both versions are up-gradable to Marshmallow. I know that the K1 is, but can anyone confirm if this is also true for the original 2014 model?

I have been offered one to buy, but I want to determine this first, but am having trouble finding out. With the models being named so similarly and the fact that both have the Nvidia Tegra K1 GPU, it's almost impossible to search on this without the two being indistinguishable.